Larissa Korde, principal researcher at the Clinical Genetics Branch Division of Cancer Epidemiology and Genetics, National Cancer Institute, US, in her report found that soy intake from childhood was significantly associated with reduced breast cancer risk.

Korde is an assistant professor in the University of Washington (UW) division of Medical Oncology.

Medical experts in India agree.

"The rate of breast cancer has always increased or decreased with food habits. Breast cancer rates are high in western nations as compared to women living in China and Japan where people consume high soy diet since childhood," says Sameer Kaul, senior consultant, oncology, at Apollo Hospital.

Soy protein is a high quality protein equivalent to the protein quality of egg, milk or meat. Soybean is a functional food of this millennium with complete protein package, containing essential amino acids that are required by the body.

With almost 40 percent protein, soybeans are higher in protein content than other legumes and numerous animal products.

According to the study, the isoflavone protein in soy inhibits the growth of cancer in men (prostate cancer) and women (breast cancer).

"Isoflavone in soybean acts like tamoxifen, a medicine which is used to cure breast cancer. Women with a high lifetime exposure to estrogen have greater risk of breast cancer. So, isoflavone exerts an anti-estrogen effect at some body tissues which may explain the reduced risk of breast cancer," said Anupama Hooda, chief of medical oncology at Max Health Care Superspeciality Hospital.

Hooda says that soy should be consumed from its natural sources - plant products like tofu and miso. Soya products like soy milk, soybean chunks, sou-flour, soy papad, soy cookies and soy namkeens can also be consumed instead of taking pills having high soy proteins.

Talking about the ill-effects of soy pills, Hooda said: "Isoflavones in the pill thickens the blood since they are processed and can bring about clumping red blood cells which is not a good sign."

"Consuming soy food consistently at an early age is always better than going for hormonal replacement therapy opted by women to remain young as it increases the period of menopause and also increases the risk of breast cancer," said Rohit V. Nayyar, senior consultant, oncology, Apollo Hospital.

The study further concluded that no significant association with soy food consumption was found for post-menopausal breast cancer.

Prostate cancers, as well as the normal prostate gland cells that give rise to prostate cancer, produce PSA (prostate-specific antigen), which allows doctors to detect new or recurrent prostate cancers by measuring the level of PSA in the blood. A newly published research study, which appears in the current issue of the journal The Prostate, adds further evidence that soy isoflavones and curcumin may have an important role to play in prostate cancer prevention and, possibly, prostate cancer treatment.

This study consisted of both a laboratory experiment and a small clinical research trial with human volunteers. In the laboratory portion of this study, human prostate cancer cells were treated with soy isoflavones and curcumin. When these prostate cancer cells were treated with soy isoflavones and curcumin, the production of PSA by these cells was dramatically decreased. Moreover, a receptor for male sex hormones, which prostate cancers use to fuel their growth, was significantly suppressed following treatment of these cells with soy isoflavones and curcumin.

In the clinical portion of this research study, men who had undergone prostate gland biopsies due to an elevated PSA blood level, but who were subsequently found not to have prostate cancer, were also evaluated. In this prospective, randomized, placebo-controlled trial, 85 men without prostate cancer, but with elevated blood PSA levels, were divided into two groups. The “experimental group” of men received curcumin and soy isoflavones once per day. The “control group” of men received a placebo (“sugar pill”) once per day. Neither group of male volunteers, nor the research assistants who dispensed these pills, knew which men received the placebo pills and which received the soy isoflavone and curcumin pills.

PSA levels were tested in all of these male volunteers at the beginning of the study, and 6 months later. Among the men randomized to receive daily supplements of soy isoflavones and curcumin, the level of PSA in their blood dramatically declined following 6 months of supplementation with soy isoflavones and curcumin. While the results of this small and elegant research study do not prove that soy isoflavones and curcumin can actually prevent prostate cancer in humans, these results do suggest, at least, a biological mechanism whereby these dietary compounds might reduce the risk of developing prostate cancer, and might also have anti-cancer effects in patients with prostate cancer. However, only large-sale prospective, randomized, blinded, placebo-controlled human clinical trials will be able to prove that these dietary compounds can actually prevent or effectively treat prostate cancer.

At this time, there are multiple ongoing and recently completed prostate cancer prevention and treatment clinical research trials using soy isoflavone supplements. The results of several of these studies will, hopefully, become available within the next 3 to 5 years.While there are multiple cancer prevention and cancer treatment research trials underway that are evaluating curcumin, none of these ongoing curcumin clinical trials are focused on prostate cancer, unfortunately.

Based upon the findings of this small and innovative research study of soy isoflavones and curcumin, the next logical step would be a large prospective, randomized, placebo-controlled, blinded study that randomizes patient volunteers to placebo, versus soy isoflavones only, versus curcumin only, versus a combination of soy isoflavones and curcumin. A cancer prevention study could look at prostate cancer incidence in men who are already at high risk of developing this common form of cancer. A prostate cancer treatment study, using the same methods, could assess the clinical impact of soy isoflavones and curcumin on the progression or recurrence of prostate cancer in men who have already been diagnosed with this form of cancer.